Settings: fix apn_editor carrier_enabled summaryOff string

Change-Id: I44ccec73601806dc8facad122f1ab16ff3aca484
Signed-off-by: Felipe Leon <fglfgl27@gmail.com>
diff --git a/res/xml/apn_editor.xml b/res/xml/apn_editor.xml
index 742a436..0c39948 100644
--- a/res/xml/apn_editor.xml
+++ b/res/xml/apn_editor.xml
@@ -148,7 +148,7 @@
         android:key="carrier_enabled"
         android:enabled="false"
         android:summaryOn="@string/carrier_enabled_summaryOn"
-        android:summaryOff="@@string/carrier_enabled_summaryOff"
+        android:summaryOff="@string/carrier_enabled_summaryOff"
         android:persistent="false"
         />
     <MultiSelectListPreference